Watchdog Timer | Philips P89LPC908, P89LPC906, P89LPC907 manual

Philips Semiconductors	User’s Manual - Preliminary -

WATCHDOG TIMER	P89LPC906/907/908

PERIODIC WAKEUP FROM POWER DOWN WITHOUT AN EXTERNAL OSCILLATOR

Without using an external oscillator source, the power consumption required in order to have a periodic wakeup is determined by the power consumption of the internal oscillator source used to produce the wakeup.The Real-time clock running from the internal RC oscillator can be used. The power consumption of this oscillator is approximately 300uA. Instead, if the WDT is used to generate interrupts the current is reduced to approximately 50uA. Whenever the WDT underflows, the device will wake up.

2003 Dec 8

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Philips P89LPC908, P89LPC906, P89LPC907 user manual Watchdog Timer

Contents

User Manual Table of Contents Power-On reset code execution Brownout Detection Power-On Detection Power Reduction Modes 103 List of Figures List of Figures P89LPC906 PIN Configurations Product Comparison Logic Symbols KB Code Flash Block Diagram P89LPC906CPU Oscillator Divider Uart Block Diagram P89LPC907Byte Data RAM Clock Data RAM Port Block Diagram P89LPC908 PIN Descriptions P89LPC906 P1.0 PIN Descriptions P89LPC907TxD P1.2 Keyboard Input P1.0 P1.5 PIN Descriptions P89LPC908P1.1 RxD Special function registers table P89LPC906 Special function registers MSB LSB Hex Special function registers table P89LPC907 CMP1 Cmpref TRIM.5 TRIM.4 TRIM.3 TRIM.2 TRIM.1 TRIM.0 WDCON# Special function registers table P89LPC908 KB2 KB6 KB5 KB4 TL0 Data Memory OrganizationSFR Code Clock Definitions Enhanced CPUCPU Clock Oscclk LOW Speed Oscillator Option P89LPC906 Clock Output P89LPC906 Oscillator Option SELECTION- P89LPC906ON-CHIP RC Oscillator Option Watchdog Oscillator Option BIT Symbol Function CPU Clock Cclk Wakeup DelayExternal Clock Input Option P89LPC906 CPU Clock Cclk Modification Divm Register High freq LOW Power Select P89LPC906Med freq Low freq CPU Clocks Interrupt Priority Structure Flag Bits Address Enable Bits Priority RankingSummary of Interrupts P89LPC906 Description Interrupt Arbitration External Interrupt PIN Glitch Suppression External Interrupt InputsSummary of Interrupts P89LPC907,P89LPC908 Description TI & RI Bopd EBO Rtcf Kbif Interrupts QUASI-BIDIRECTIONAL Output Configuration Port ConfigurationsNumber of I/O Pins Available Clock Source Reset Option RST Port latch data Open Drain Output Configuration PUSH-PULL Output Configuration INPUT-ONLY ConfigurationPort 0 Analog Functions Strong Port latch data Port pin Input data Glitch rejection Port Output Configuration P89LPC907 Port Output Configuration P89LPC906Port Output Configuration P89LPC908 Ports Ports TMOD.7 TmodTMOD.6 TMOD.3 Mode Overflows. ModeTamod P89LPC907 TAMOD.7-1 Tcon T0C/T = Overflow TLn THn TFn Interrupt T0 Pin PclkT0C/T = Overflow THn TFn Pclk TL0 Timer Overflow Toggle Output P89LPC907TR0 ENT0 Pclk TH0 Timers 0 REAL-TIME Clock Source UCFG1.2 UCFG1.1 UCFG1.0 Cclk Frequency RTC Clock Frequency FOSC2 FOSC1 FOSC0 RTCS10Xclk Divm Cclk WDT Oscillator/DIVM RC Oscillator/DIVMUndefined External clock/DIVM Changing RTCS1-0 Reset Sources Affecting the REAL-TIME ClockREAL-TIME Clock INTERRUPT/WAKE UP Rtccon REAL-TIME CLOCK/SYSTEM Timer Brownout Detection Power Reduction Modes POWER-ON DetectionBrownout Options Power Reduction Modes Pcon Pcona Power Monitoring Functions Modes Uart Baud Rate Generator and Selection SFR SpaceUpdating the BRGR1 and BRGR0 Sfrs SFR Locations for UARTs Break Detect Framing ErrorBrgcon Scon Sstat More about Uart Mode Serial Port Mode 0 Double Buffering Must Be Disabled FE and RI when SM2 = 1 in Modes 2 Framing Error and RI in Modes 2 and 3 with SM2 =More about Uart Modes 2 PCON.6 RB8 SMOD0 Double Buffering in Different Modes Double Buffering Transmission with and without Double Buffering 9TH BIT BIT 8 in Double Buffering Modes 1, 2 Automatic Address Recognition Multiprocessor Communications Uart Uart Block Diagram of Reset POWER-ON Reset Code Execution Rstsrc Comparator Configuration Internal Reference Voltage Comparator and Power Reduction ModesComparator Interrupt CIN1A CO1 CMP1 Cmpref Comparator Configuration Example Analog Comparators Kbcon Kbpatn Kbmask Watchdog Function Watchdog timer configurationWdte Wdse Function Feed Sequence Wdcon PRE2-PRE0 P89LPC906/907/908 Watchdog Timeout Values Prescaler Reset Pclk Watchdog Timer in Timer ModeWatchdog Control register Watchdog Clock Source Power Down OperationPrescaler CLK Watchdog Timer Watchdog Timer Dual Data Pointers Software ResetAUXR1 Move code byte relative to Dptr to the accumulator MOVCA, @A+DPTRMOVXA, @DPTR MOVX@DPTR, a Using Flash AS Data Storage FeaturesGeneral Description Introduction to IAP-LITE Flash Program Memory Fmcon Assembly language routine to erase/program all or part of a Accessing Additional Flash Elements Reading Additional Flash Elements ERASE-PROGRAMMING Additional Flash ElementsUCFG1 Fmadrl Conf UCFG1 User Configuration BytesP89LPC906 SECx User Security BytesAddress xxxxh Unprogrammed value 00h Bootstat Bootvec Logical Arithmetic Data Transfer Mnemonic Description Bytes Cycles Hex Code Branching Boolean B8-BF RetiD8-DF Miscellaneous 2003 Dec Initial release 104 Index Dual Data Pointers Port 0 12, 13 SFR 109 P89LPC906/907/908